hsta_msi.c

  1// SPDX-License-Identifier: GPL-2.0-or-later
  2/*
  3 * MSI support for PPC4xx SoCs using High Speed Transfer Assist (HSTA) for
  4 * generation of the interrupt.
  5 *
  6 * Copyright © 2013 Alistair Popple <alistair@popple.id.au> IBM Corporation
  7 */
  8
  9#include <linux/kernel.h>
 10#include <linux/interrupt.h>
 11#include <linux/msi.h>
 12#include <linux/of.h>
 13#include <linux/of_irq.h>
 14#include <linux/platform_device.h>
 15#include <linux/pci.h>
 16#include <linux/semaphore.h>
 17#include <asm/msi_bitmap.h>
 18#include <asm/ppc-pci.h>
 19
 20struct ppc4xx_hsta_msi {
 21	struct device *dev;
 22
 23	/* The ioremapped HSTA MSI IO space */
 24	u32 __iomem *data;
 25
 26	/* Physical address of HSTA MSI IO space */
 27	u64 address;
 28	struct msi_bitmap bmp;
 29
 30	/* An array mapping offsets to hardware IRQs */
 31	int *irq_map;
 32
 33	/* Number of hwirqs supported */
 34	int irq_count;
 35};
 36static struct ppc4xx_hsta_msi ppc4xx_hsta_msi;
 37
 38static int hsta_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
 39{
 40	struct msi_msg msg;
 41	struct msi_desc *entry;
 42	int irq, hwirq;
 43	u64 addr;
 44
 45	/* We don't support MSI-X */
 46	if (type == PCI_CAP_ID_MSIX) {
 47		pr_debug("%s: MSI-X not supported.\n", __func__);
 48		return -EINVAL;
 49	}
 50
 51	msi_for_each_desc(entry, &dev->dev, MSI_DESC_NOTASSOCIATED) {
 52		irq = msi_bitmap_alloc_hwirqs(&ppc4xx_hsta_msi.bmp, 1);
 53		if (irq < 0) {
 54			pr_debug("%s: Failed to allocate msi interrupt\n",
 55				 __func__);
 56			return irq;
 57		}
 58
 59		hwirq = ppc4xx_hsta_msi.irq_map[irq];
 60		if (!hwirq) {
 61			pr_err("%s: Failed mapping irq %d\n", __func__, irq);
 62			return -EINVAL;
 63		}
 64
 65		/*
 66		 * HSTA generates interrupts on writes to 128-bit aligned
 67		 * addresses.
 68		 */
 69		addr = ppc4xx_hsta_msi.address + irq*0x10;
 70		msg.address_hi = upper_32_bits(addr);
 71		msg.address_lo = lower_32_bits(addr);
 72
 73		/* Data is not used by the HSTA. */
 74		msg.data = 0;
 75
 76		pr_debug("%s: Setup irq %d (0x%0llx)\n", __func__, hwirq,
 77			 (((u64) msg.address_hi) << 32) | msg.address_lo);
 78
 79		if (irq_set_msi_desc(hwirq, entry)) {
 80			pr_err(
 81			"%s: Invalid hwirq %d specified in device tree\n",
 82			__func__, hwirq);
 83			msi_bitmap_free_hwirqs(&ppc4xx_hsta_msi.bmp, irq, 1);
 84			return -EINVAL;
 85		}
 86		pci_write_msi_msg(hwirq, &msg);
 87	}
 88
 89	return 0;
 90}
 91
 92static int hsta_find_hwirq_offset(int hwirq)
 93{
 94	int irq;
 95
 96	/* Find the offset given the hwirq */
 97	for (irq = 0; irq < ppc4xx_hsta_msi.irq_count; irq++)
 98		if (ppc4xx_hsta_msi.irq_map[irq] == hwirq)
 99			return irq;
100
101	return -EINVAL;
102}
103
104static void hsta_teardown_msi_irqs(struct pci_dev *dev)
105{
106	struct msi_desc *entry;
107	int irq;
108
109	msi_for_each_desc(entry, &dev->dev, MSI_DESC_ASSOCIATED) {
110		irq = hsta_find_hwirq_offset(entry->irq);
111
112		/* entry->irq should always be in irq_map */
113		BUG_ON(irq < 0);
114		irq_set_msi_desc(entry->irq, NULL);
115		msi_bitmap_free_hwirqs(&ppc4xx_hsta_msi.bmp, irq, 1);
116		pr_debug("%s: Teardown IRQ %u (index %u)\n", __func__,
117			 entry->irq, irq);
118		entry->irq = 0;
119	}
120}
121
122static int hsta_msi_probe(struct platform_device *pdev)
123{
124	struct device *dev = &pdev->dev;
125	struct resource *mem;
126	int irq, ret, irq_count;
127	struct pci_controller *phb;
128
129	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
130	if (!mem) {
131		dev_err(dev, "Unable to get mmio space\n");
132		return -EINVAL;
133	}
134
135	irq_count = of_irq_count(dev->of_node);
136	if (!irq_count) {
137		dev_err(dev, "Unable to find IRQ range\n");
138		return -EINVAL;
139	}
140
141	ppc4xx_hsta_msi.dev = dev;
142	ppc4xx_hsta_msi.address = mem->start;
143	ppc4xx_hsta_msi.data = ioremap(mem->start, resource_size(mem));
144	ppc4xx_hsta_msi.irq_count = irq_count;
145	if (!ppc4xx_hsta_msi.data) {
146		dev_err(dev, "Unable to map memory\n");
147		return -ENOMEM;
148	}
149
150	ret = msi_bitmap_alloc(&ppc4xx_hsta_msi.bmp, irq_count, dev->of_node);
151	if (ret)
152		goto out;
153
154	ppc4xx_hsta_msi.irq_map = kmalloc_array(irq_count, sizeof(int),
155						GFP_KERNEL);
156	if (!ppc4xx_hsta_msi.irq_map) {
157		ret = -ENOMEM;
158		goto out1;
159	}
160
161	/* Setup a mapping from irq offsets to hardware irq numbers */
162	for (irq = 0; irq < irq_count; irq++) {
163		ppc4xx_hsta_msi.irq_map[irq] =
164			irq_of_parse_and_map(dev->of_node, irq);
165		if (!ppc4xx_hsta_msi.irq_map[irq]) {
166			dev_err(dev, "Unable to map IRQ\n");
167			ret = -EINVAL;
168			goto out2;
169		}
170	}
171
172	list_for_each_entry(phb, &hose_list, list_node) {
173		phb->controller_ops.setup_msi_irqs = hsta_setup_msi_irqs;
174		phb->controller_ops.teardown_msi_irqs = hsta_teardown_msi_irqs;
175	}
176	return 0;
177
178out2:
179	kfree(ppc4xx_hsta_msi.irq_map);
180
181out1:
182	msi_bitmap_free(&ppc4xx_hsta_msi.bmp);
183
184out:
185	iounmap(ppc4xx_hsta_msi.data);
186	return ret;
187}
188
189static const struct of_device_id hsta_msi_ids[] = {
190	{
191		.compatible = "ibm,hsta-msi",
192	},
193	{}
194};
195
196static struct platform_driver hsta_msi_driver = {
197	.probe = hsta_msi_probe,
198	.driver = {
199		.name = "hsta-msi",
200		.of_match_table = hsta_msi_ids,
201	},
202};
203
204static int hsta_msi_init(void)
205{
206	return platform_driver_register(&hsta_msi_driver);
207}
208subsys_initcall(hsta_msi_init);